Adjustable eccentric for sewing machines



June 12, 1956 E. s. ROCKNEY 2,749,360

ADJUSTABLE ECCENTRIC FOR SEWING MACHINES Filed Nov. 1, 1954 7 Sheets-Sheet 1 June 12, 1956 E. s ROCZKNEY ADJUSTABLE ECCENTRIC FOR sswmc MACHINES Filed Nov. 1, 1954 7 Sheets-Sheet 2 NGE June 12, 1956 E. s. ROCKNEY ADJUSTABLE ECCENTRIC FOR SEWING MACHINES 7 Sheets-Sheet 5 Filed Nov. 1, 1954 FIG.4

June 12, 1956 E. s. ROCKNEY ADJUSTABLE ECCENTRIC FOR SEWING MACHINES 7 Sheets-Sheet 4 Filed Nov. 1, 1954 June 12, 1956 E. s. ROCKNEY ADJUSTABLE ECCENTRIC FOR SEWING MACHINES 7 Sheets-Sheet 5 Filed Nov. 1, 1954 June 12, 1956 E. s. ROCKNEY ADJUSTABLE ECCENTRIC FOR SEWING MACHINES 7 Sheets-Sheet 6 Filed Nov. 1, 1954 June 12, 1956 E. s. ROCKNEY 2,749,860

ADJUSTABLE ECCENTRIC FOR SEWING MACHINES Filed Nov. 1, 1954 7 Sheets-Sheet '7 ADJUSTABLE ECCENTREC FGR SEWING MACHENES Elton S. Rockney, Floral Park, N. Y., assignor to Union Special Machine Qornpauy, Chicago, iii, a corporation of Illinois Application November 1, 1954, Serial No. 465,823

11 Claims. (ill. 112-210) This invention relates to an improved adjustable eccentric assembly for use in operating the work feeding mechanism of a sewing machine.

In the use of various industrial sewing machines, it is frequently found desirable to change the stitch length, determined by the work feeding mechanism, for the performance of different seaming operations on various portions of garments or other articles. As a typical example, it is usually found desirable to attach cuff members to shirts firstly by a line of stitching having say 12 stitches to the inch. After this operation has been performed the cults are folded upon themselves and stitched by means of a seam having say 16 stitches to the inch. In machines as heretofore constructed a substantial amount of time is lost in making the changeover from one stitch length to the other.

A primary object of the present invention has been to provide an adjustable eccentric which may be very simply and quickly changed from one definite throw to another definite throw. in the use of such an eccentric for the driving of work feeding mechanism, such as a four-motion feed dog, it is thus possible to change quickly and readily from one stitch length to another. Such change is made only periodically and does not require manipulation of any devices in the course of operating the sewing machine. Thus in perf ruling the two seaming operations explained above, in the attachment of cuffs to shirts, the operator will perform the first seaming operation on a large number of units embraced in one or more bundles. Upon completion of this operation on all of the plurality of units the cuffs will be folded as explained and the second seaming operation will be performed on the same bundle or bundles of units. Prior to performance of the second seaming operation the eccentric of the present invention will be adjusted, in the manner to be explained more fully hereinafter, so that the second predetermined stitch length may be provided for the entire group of units.

An important feature of the invention is the provision of an adjustable eccentric unit in which adjustment of its throw is accomplished by relative turning of twotelescopically arranged eccentric elements and in the provision of readily adjustable stops for predetermining two relative angular positions of the eccentric elements. One of the adjustable stops will predetermine one stitch length and the other adjustable stop will predetermine the other desired stitch length.

A special feature of the invention identified with the foregoing is the provision for infinite variation in the adjustment of the stops mentioned within the overall limits of the construction.

Another special feature is the arrangement of the adjustable stops in such a way that they are accessible from the peripheral edge of a cylindrical housing forming part of the eccentric unit so that these stops are capable of ready adjustment from one position to another.

While the invention is primarily directed to the provision of means for readily and quickly changing the stitch res Patent Zfllhfififi Patented June 12, 1956 length of a sewing machine, the adjustable stop elements referred to above be used advantageously to hold the adjustable eccentric unit in a single set position identiiied with a particular stitch length so that the operator will not change the stitch length in the course of operating the machine.

Other objects, features, and advantages of the invention will appear from the detailed description of an illustrative form of the same which will now be given in conjunction with the accompanying drawings in which:

Fig. 1 is a view partly in elevation but largely in longitudinal vertical section through a sewing machine embodying the invention;

Fig. 2 is a bottom view of the machine, certain parts being broken away to illustrate some of the details of the construction;

Fig. 3 is a view partially in end elevation and partially in transverse vertical section through the lower portion of the machine illustrated in Fig. 1;

Fig. 4 is a vertical sectional view taken along the line 4-4 of Fig. 2;

Fig. 5 is a vertical sectional view through the lower portion of the machine taken along the line 55 of Fig. 1;

Fig. 6 is an end elevational view of the base portion of the machine, as seen from the left in Fig. 1, certain parts being broken away for clarity of illustration;

Fig. 7 is a detail View, in plan, of the improved adjustable eccentric unit shown mounted on a section of the drive shaft;

Fig. 8 is a longitudinal sectional view through the parts shown in Fig. 7;

Fig. 9 is an end elevatio-nal view of the parts shown in Fig. 7 as seen from the left;

Fig. 10 is an enlarged detail view of the parts shown in Fig. 7, partly in vertical section and partly in elevation;

Fig. 11 is a vertical sectional view through the adjustable eccentric unit taken along the line 1111 of Fig. 8;

Fig. 12 is an end elevational view of the eccentric unit as seen from the right in Fig. 7; and

Fig. 13 is an exploded perspective view of the various parts incorporated in the adjustable eccentric including certain elements which cooperate therewith.

Referring now to the drawings, the invention has been illustrated as applied to a lockstitch sewing machine of the character shown in the patent to Reimer No. 2,643,625, granted June 30, 1953. It has a main frame comprising a work supporting base portion 10, a vertical standard 11, an overhanging arm 12 extending laterally from the standard over the work supporting base and terminating in a needle head 13. A main drive shaft 14 is suitably journaled in the overhanging arm 12 and the top of the vertical standard and extends outwardly beyond the latter to carry a combined handwheel and pulley 15 by means of which the machine is driven. Within the needle head the shaft 14 carries a crank element 16 which is connected by a link 17 with a vertically reciprocable needle bar 13 carrying a needle 19 at its lower end. Within the vertical standard gearing 20, 21, and 22 serves to connect the main drive shaft 14 with a rotary shaft 23 in the work supporting base of the machine. Shaft 23 has secured thereto a gear 24 which meshes with a pinion 25 secured to a shaft 26, which is suitably journaled in the base and carries at its left end (Fig. 2) a rotary hook 27 of well-known construction. The arrangement is such that the rotary component of the hook is driven at double the angular speed of the shafts 14 and 23. It will be understood that the rotary hook cooperates with the needle to form lockstitches in the course of a seaming operation. A presser foot 28 (Fig. 3) is secured to the lower end of a presser bar 29 which is spring urged downwardly but mounted for limited up and down movement within the needle head. The presser foot serves to retain the work against the work supporting surface of the base and in cooperation with a four-motion feed dog to be described.

For advancing the work intermittently to desired extents, a four-motion feed dog 30 (Figs. 3 and 6) is adjustably mounted on a feed bar 31 having a hub portion 32 at its rearward end secured to a pin 33 rockably mounted in upstanding arms of a feed rocker 34. The latter is secured to a pin or rock shaft 35 suitably journaled in bearings provided in the base portion of the frame. A pin 36, rockably mounted in the feed rocker, has secured thereto a hub element formed at the rear end of a pitman 37 (Fig. 3) having a strap at its opposite end arranged to surround the eccentric unit to be described. Strap 38 is preferably provided with a needle bearing unit 38a (Fig. 13) for cooperation with the operating eccentric surface of the adjustable eccentric unit.

It will be understood that feed and return movements are imparted to the feed dog 30 through the rocking of the feed rocker by virtue of the action of the adjustable eccentric. Lifting and lowering movements are imparted to the feed dog through a downwardly and forwardly extending arm 39 integral with or otherwise carried by the feed bar 31. The forward end of this arm is pivotally connected with the lower end of a pitrnan 40 having a strap at its upper end which cooperates with an eccentric provided at the left end (Fig. 2) of the shaft 23.

Referring now particularly to Figs. 7 to 13 inclusive, the construction of the improved adjustable eccentric unit will be described. This unit is in many respects similar to that disclosed in the above-mentioned patent to Reimer No. 2,643,625. It embodies an inner eccentric element 41 which, in a typical unit, has been provided with an eccentricity of .032 inch. This element is capable of being turned in relation to the shaft 23 on which it is mounted but normally rotates with the latter due to the frictional forces created within the unit. Fitted telescopically over the element 41 is an outer eccentric element 42 which in a typical unit has been provided with an eccentricity of .040 inch. It has been found possible with this combination of eccentrics to vary the stitch length imparted to the work feeding mechanism between 4 /2 stitches per inch to 26 stitches per inch. This is a quite satisfactory range for practically all uses of the machine. As will be understood, the relative turning of the two eccentric elements 41 and 42 serves to vary the overall eccentricity of the outer surface of element 42 in relation to the axis of the shaft 23.

The outer eccentric element 42 is provided with an enlarged end portion 43 cut away in part over an arc of about 150 to enable the relative turning of the two eccentric elements. In the outer end of the enlarged portion 43 there is provided a notch 43b arranged to receive a key element 44 having a pin-like shank 45 which fits within an opening 45a extending transversely through a disk-like element 46 which is secured to the shaft 23 by means of a plurality of set screws 46a. It will be apparent that by virtue of this connection the outer eccentric element 42 will be rotated at all times with the shaft 23. A housing member 47 surrounds a portion of the outer eccentric element 42 with appropriate clearance in relation to the enlarged portion 4-3 thereof. Housing 47 is secured to the element 46 by means of a plurality of screws 48. As will appear more clearly as the description progresses, the housing 47 serves to retain the various parts of the adjustable eccentric unit in assembled relation to provide a unitary assembly. The housing has an inwardly extending flange portion 51 at its inner end which cooperates with the adjacent face of the enlarged portion of the eccentric element 42 to retain this against outward movement toward the left (Fig. Inner eccentric element 41 has a radially eXtending flange 52 at its end within the housing 47 and this flange carries a projection 53 which, as will be explained, cooperates with certain steps to limit the extent of rotation of the inner eccentric in relation to the housing and outer eccentric. A facing or lining 54 formed of suitable friction material is applied by an appropriate adhesive or other securing means to the outer face of the flange 52. This facing is preferably of the same contour as the flange and its projection 53. A helical spring 55 surrounding the eccentric element 41 within the housing 47 bears at one end against the inner face of the flange 52 and at its other end against an interior surface of the outer eccentric 42. This spring serves to retain the parts in the relationship shown in Figs. 8 and 10. It also serves to create a suitable friction force between the facing 54 and the inner wall of the element 46 to cause the eccentric element 41 to rotate normally with the shaft 23 and the outer eccentric and related parts. The friction for this purpose is supplemented by the relatively close fit between the inner eccentric and the shaft and the outer eccentric. However, it may be overcome by the application of suitable force, while the inner eccentric is firmly held against turning with the shaft 23, to bring about relative angular adjustment of the inner and outer eccentrics.

At the free end of the eccentric portion of element 41 there is provided a slot or notch 56 arranged to be entered by a finger 57 carried by an arm 58 secured to a rock shaft 59 by means of set screws 60 (Fig. 3). The notch and finger may suitably have the form disclosed in the above mentioned patent to Reimer. Shaft 59 extends parallel with the shaft 23 through the work supporting base of the frame and into the space below the vertical standard. Here, it carries an arm 61 which is urged in a counterclockwise (Fig. 5) direction by a coil spring 62. One end of this spring engages a projection on the arm 61 and the other end is held by a recess in a bracket 63 carried by the frame. Rocking of the shaft 59 by means of the spring causes the arm 61 to engage the end of a push rod 64 and forces this outwardly to a position in which a collar 64a on the rod engages a portion of the frame. At this time the finger 57 is out of engagement with the notch 56 and is in the position shown in Fig. 3. The rod 64 extends outwardly through the front wall of the vertical standard and is provided at its outer end with a knob or button 65 by means of which it may be pressed inwardly to cause the arm 61 and shaft 59 to be rocked in a clockwise direction (Fig. 5). Upon such rocking of the shaft 59 the finger 57 of the arm 58 is brought against the periphery of the inner eccentric 41. When the operator now turns the handwheel 15 the notch or groove 56 may be brought into alinement with the finger 57 and the latter may then be urged into the notch by further pressure on the knob 65. When the parts are in this condition, turning of the handwheel in either direction will cause the shaft 23 to turn the outer eccentric 42 in relation to the inner eccentric 41 which is being held against turning. When the desired adjustment has been achieved the knob 65 is released and the detent finger 57 is retracted by the action of the spring 62. To assist in determining the desired adjustment of the eccentric unit the shaft 23 may be provided with an indicator wheel 66 which is visible through a transparent disc 66a provided in the work supporting surface of the base of the frame. Wheel 56 may carry suitable indicia to designate the particular stitch length for which the adjustable eccentric has been set, these indicia being read in relation to an index mark on the disc 66a.

As a special feature of the present invention the housing 47 is provided with a pair of adjustable stops 67 having portions in the path of the projection 53 on the flange 52 of the inner eccentric. These stops may suitably have the configuration best shown in Fig. 13. Each may be of block-like form and have a reduced portion 68 arranged to extend into an elongated slot 69 provided circumferentially over a suitable are around the cylindrical wall of the housing 47. If desired thetwo slots 69 shown may be replaced by a single long slot extending a suitable distance circumferentially around the wall of the housing to enable adjustment of the stops to any selected position along the slot. Arcuate shoulders 70 on the stop 67 conform with the contour of the inner wall of the housing 47. The stops may be adjusted to any suitable position along the elongated slots 69 and then secured in said position by tightening of screws 71.

In the use of the invention to carry out the specific operation mentioned earlier herein, for the attachment of cuffs to shirts, the eccentric may be adjusted in the manner explained above to correspond with a stitch length of 12 stitches to the inch. One of the blocks 67 may then be adjusted and set in a position in which a face or shoulder thereof cooperates with one of the radial edges of the projection 53 of the flange 52. The adjustable eccentric may then be readjusted toprovide 16 stitches to the inch and the other stop 67 may be set in a position in which one face engages the opposite edge of the projection 53. When this has been done it becomes a very simple matter for the operator to change from one predetermined stitch length to the other in the course of repeatedly dealing with bundles of work requiring the two stitch lengths to be employed in different seams. If a new batch of work requires seams having a different combination of stitch lengths, the stops 67 are released for movement along the slots 69 by loosening the screws 71 and are then reset in the proper positions to provide the desired stitch lengths, in the manner explained above.

To facilitate the initial adjustment of the stops 67 suitable indicia 72 (Fig. 7) may be provided on the peripheral surface of the housing 47 adjacent the elongated slots 69. These indicia may correspond with those appearing on the wheel 66 and indicate, in correlation with the centers of screws 71, the particular stitch length for which each of the stops 67 is set.

In the event that it is desired to lock the eccentric against any adjustment, the two stops 67 may be brought against the opposite edges of the projection 53 after this has been positioned in accordance with the desiredstitch length.

While a preferred embodiment of the invention has been described in considerable detail, it will be understood that various changes may be made in the construction and arrangement of the several parts within the scope of the appended claims. The new adjustable eccentric unit may be employed advantageously for the operation of other forms of work advancing means or other elements of a sewing machine requiring rather frequent changes from one predetermined but variable stroke to another predetermined but variable stroke.

I claim:

1. In a sewing machine having a frame and a rotary drive shaft journaled therein, work feeding mechanism carried by said frame, connections from said. shaft for operating said work feeding mechanism, said connections comprising an adjustable eccentric unit driven by said shaft, said eccentric unit comprising a plurality of telescopically disposed eccentric elements arranged for relative angular adjustment to vary the throw ofsaid unit, means for adjusting said eccentric elements angularlyin relation to each other, adjustable stop means connected with one of said eccentric elements for rotation therewith, said stop means being adjustable to any desired extent within predetermined limits in relation to said one of said eccentric elements, means for securing said stop means in any selected position in relation to said one of said eccentric elements, and means on another of said eccentric elements arranged to cooperate with said stop means upon relative angular adjustment of said eccentric elements to predetermine a plurality'of relative angular positions of said eccentric elements.

2. In a sewing machine having a frame and a rotary drive shaft journaled therein, work feeding mechanism carried by said frame, connections from said shaft for operatingsaid work feeding mechanism, said connections comprising an adjustable eccentric unit driven by said shaft, said eccentric unit comprising a plurality of telescopically disposed eccentric elements arranged for relative angular adjustment to vary the throw of said unit, means for adjusting said eccentric elements angularly in relation to each other, adjustable stop means connected with one of said eccentric elements for rotation therewith, said stop means being adjustable to any desired extent within predetermined limits in relation to said one of said eccentric elements, means for securing said stop means in any selected position in relation to said one of said eccentric elements, said securing means extending radially from said one of said eccentric elements and being operable to secure or release said stop means from points radially outwardly from said one of said eccentric elements, and means on another of 'said eccentric elements arranged to cooperate with said stop means upon relative angular adjustment of said eccentric to predetermine a plurality of relative angular positions of said eccentric elements.

3. 1n a sewing machine having a frame and a rotary drive shaft journaled therein, work feeding mechanism carried by said frame, connections from said shaft for operating said work feeding mechanism, said connections comprising an adjustable eccentric unit driven by said shaft, said eccentric unit comprising a plurality of telescopically disposed eccentric elements arranged for relative angular adjustment to vary the throw of said unit, means for adjusting said eccentric elements angularly in relation to each other, a pair of adjustable stop means carried by one of said eccentric elements, each of said stop means having a screw threaded securing element, a member surrounding a portion of said one of said eccentric elements and connected for rotation in unison therewith, said member having an arcuate slot arranged to receive said screw threaded securing element for each of said stop means whereby the latter may be secured to said member in any desired position along said slot, and means connected with another of said eccentric elements and movable therewith into selective engagement with one or the other of said stop means upon relative angular adjustment of said eccentric elements to thereby determine specific angular relationships between said eccentric elements.

4. In a sewing machine having a frame and a rotary drive shaft journaled therein, work feeding mechanism carried by said frame, connections from said shaft for operating said work feeding mechanism to advance the work a predetermined extent upon each revolution of said shaft, said connections comprising a pair of telescopically disposed eccentric elements mounted on said shaft, one of said elements being positively connected with said shaft for rotation therewith, the other of said elements being frictionally connected with said shaft and with said one of said elements for rotation therewith in the normal operation of said machine, means operable at will for preventing rotation of said other of said elements upon rotation of said shaft to effect relative angular adjustment of said elements to vary the combined eccentricity thereof, one of said eccentric elements having a projection rotatable therewith and the other of said elements having a pair of adjustable stops mounted thereon in the path of said projection, said stops being adjustable infinitely within predetermined limits in relation to said other of said elements and serving to determine two definite relative angular positions of said eccentric elements upon relative angular adjustment thereof.

5'. In a sewing machine having a frame and a rotary drive shaft journaled therein, work feeding mechanism carried by said frame, connections from said shaft for operating said work feeding mechanism to advance the work a predetermined extent upon each revolution of said shaft, said connections comprising a pair of telescopically disposed eccentric elements mounted on said shaft, one of said elements being positively connected with said shaft for rotation therewith, the other of said elements being frictionally connected with said shaft and with said one of said elements for rotation therewith in the normal operation of said machine, means operable at will for preventing rotation of said other of said elements upon rotation of said shaft to effect relative angular adjustment of said elements to vary the combined eccentricity thereof, one of said eccentric elements having a projection rotatable therewith and the other of said elements having a pair of adjustable stops mounted thereon in the path of said projection, said stops being adjustable infinitely within predetermined limits in relation to said other of said elements and serving to determine two definite relative angular positions of said eccentric elements upon relative angular adjustment thereof, and releasable securing means for said stops accessible from the periphery of said other of said elements.

6. In a sewing machine having a frame and a rotary drive shaft journaled therein, work feeding mechanism carried by said frame, connections from said shaft for operating said work feeding mechanism to advance the work a predetermined extent upon each revolution of said shaft, said connections comprising a pair of telescopically disposed eccentric elements mounted on said shaft, one of said elements being positively connected with said shaft for rotation therewith, the other of said elements being frictionally connected with said shaft and with said one of said elements for rotation therewith in the normal operation of said machine, means operable at will for preventing rotation of said other of said elements upon rotation of said shaft to effect relative angular adjustment of said elements to vary the combined eccentricity thereof, one of said eccentric elements having a projection rotatable therewith and the other of said elements having a pair of adjustable stops mounted thereon in the path of said projection to predetermine two definite but variable relative angular positions of said I eccentric elements upon angular adjustment thereof, said other of said elements having a circumferentially extending member connected therewith, said member having a circumferentially extending opening therethrough radially aligned with each of said stops, and means cooperating with said opening for securing said stops in any desired position in relation thereto.

7. In a sewing machine having a frame and a rotary drive shaft journaled therein, work feeding mechanism carried by said frame, connections from said shaft for operating said work feeding mechanism to advance the work a predetermined extent upon each revolution of said shaft, said connections comprising an adjustable eccentric unit mounted on said shaft, said unit having a pair of telescopically disposed eccentric elements, the innermost of said elements being frictionally connected with said shaft for rotation herewith in the normal operation of the machine, a housing member enclosing a portion of said unit, said housing member being connected with said shaft and with the outermost of said eccentric elements and coupling the same positively for rotation in unison, means for detaining said innermost element against rotation with said shaft to effect relative angular adjustment between'said elements, and relatively adjustable abutment means carried by said innermost element and said housing member for predetermining two definite angular relationships between said elements upon relative angular adjustment thereof, said abutment means being infinitely adjustable relative to each other within a predetermined range.

8. In a sewing machine having a frame and a rotary drive shaft journaled therein, work feeding mechanism carried by said frame, connections from said shaft for operating said work feeding mechanism to advance the work a predetermined extent upon each revolution of said shaft, said connections comprising an adjustable eccentric unit mounted on said shaft, said unit having a pair of telescopically disposed eccentric elements, the in nermost of said elements being frictionally connected with said shaft for rotation therewith in the normal operation of the machine, a housing member enclosing a portion of said unit, said housing member being connected with said shaft and with the outermost of said eccentric elements and coupling the same positively for rotation in unison, means for detaining said innermost element against rotation with said shaft to effect relative angular adjustment between said elements, and relatively adjustable abutment means carried by said innermost element and said housing member for predetermining two definite angular relationships between said elements upon relative angular adjustment thereof, certain of said abutment means being shiftable in relation to another of said abutment means to vary said definite angular relationships as desired, said shiftable abutment means being accessible for adjustment at the periphery of said housing member.

9. In a sewing machine having a frame and a rotary drive shaft journaled therein, work feeding mechanism carried by said frame, connections from said shaft for operating said work feeding mechanism to advance the work a predetermined extent upon each revolution of said shaft, said connections comprising an adjustable eccentric unit mounted on said shaft, said unit having a pair of telescopically disposed eccentric elements, the innermost of said elements being frictionally connected with said shaft for rotation herewith in the normal operation of the machine, a housing member enclosing a portion of said unit, said housing member being connected with said shaft for rotation therewith in the normal operelements and coupling the same positively for rotation in unison, means for detaining said innermost element against rotation with said shaft to effect relative angular adjustment between said elements, and relatively adjustable abutment means carried by said innermost element and said housing member for predetermining two definite angular relationships between said elements upon relative angular adjustment thereof, one of said abutment means being disposed in fixed relation to said innermost element, and a pair of said abutment means being independently adjustable circumferentially of said housing member.

10. In a sewing machine having a frame and a rotary drive shaft journaled therein, work feeding mechanism carried by said frame, connections from said shaft for operating said work feeding mechanism to advance the work a predetermined extent upon each revolution of said shaft, said connections comprising an adjustable eccentric unit mounted on said shaft, said unit having a pair of telescopically disposed eccentric elements, the innermost of said elements being frictionally connected with said shaft for rotation therewith in the normal operation of the machine, a housing member enclosing a portion of said unit, said housing member being connected with said shaft and with the outermost of said eccentric elements and coupling the same positively for rotation in unison, means for detaining said innermost element against rotation with said shaft to effect relative angular adjustment between said elements, and relatively adjustable abutment means carried by said innermost element and said housing member for predetermining two definite angular relationships between said elements upon relative angular adjustment thereof, one of said abutment means being disposed in fixed relation to said innermost element, and a pair of said abutment means being independently adjustable circumferentially of said housing member, each of said pair of abutment means having a screw threaded securing device shiftable to any selected position along a circumferentially extending slot in said housing member.

11. In a sewing machine having a frame and a rotary drive shaft journaled therein, means carried by said frame cooperating with the work in advancing the same as successive stitches are formed in the work, connections from said shaft for operating said means to variable extents along the line of feed, said connections comprising a plurality of telescopically disposed eccentric elements arranged for relative angular adjustment to vary the throw of said unit, means for adjusting said eccentric elements angularly in relation to each other, adjustable stop means connected with one of said eccentric elements for rotation therewith, said stop means being adjustable to any desired extent within predetermined limits in relation to said one of said eccentric elements, a projection carried by another of said eccentric elements for cooperation with said adjustable stop means to predetermine different but variable angular relationships between said eccentric elements upon angular adjustment thereof, means for securing said adjustable stop means in any selected position in relation to said one of said eccentric elements, said securing means extending radially from said one of said eccentric elements and being operable to secure or release said stop means from points radially outwardly from said one of said eccentric elements.

Reimer June 30, 1953 Eriksson Aug. 24, 1954 

